Your standard non-medical person most likely does not know this term unless they or someone they know has an issue with theirs. Proprioception is a system in our body that helps with balance and basically it’s the brain and body’s ability to know where it is in space.
This is why if you are the average person you can close your eyes and touch the tip of your nose with your finger. Your muscles and brain know where your finger is in relation to your nose and you do not need to see it to touch it.
From Wikipedia: “The central nervous system integrates proprioception and other sensory systems, such as vision and the vestibular system, to create an overall representation of body position, movement, and acceleration.” Also, “There are specific nerve receptors for this form of perception termed “proprioreceptors”, just as there are specific receptors for pressure, light, temperature, sound, and other sensory experiences.”
This article on Healthline states “Sensory receptors are located on your skin, joints, and muscles. When we move, our brain senses the effort, force, and heaviness of our actions and positions and responds accordingly.” Drinking alcohol can temporarily impair this function but damage can be more permanent if there are medical issues that affect muscles, nerves or the brain.
Myself and both of my children are hyper-mobile, this means we can move our limbs further than normal because our ligaments are looser. This also allows the joints to move outward further than typical. My oldest son can move his arm around his head to the point that his shoulder disappears, it’s a disturbing party trick. Myself, I notice at this age the only the only extended movement are my hips and neck and I only notice that during physical therapy or adjustments when they move them. My youngest has more loose ligaments in his lower body which causes some balance issues and since part of this system is regulated within the joints.
For myself, my MS has caused some damage to the proprioception and nerves so my balance has been impacted. Between lesions and nerve damaged I have a hard time telling where my body is in space. I watch my feet when I walk if my service dog is not with me, I have night lights around the house so I can navigate in the dark. I frequently bump into things, tripping is my super power and I couldn’t pass a roadside test 100% sober.
Multiple Sclerosis is one of the leading causes of permanent loss of proprioception. This can be caused by nerve damage or lesions in the brain connecting to the pathways.
There are physical therapy exercises that can be done to help and continued practice but it takes a lot of work and it cannot be corrected permanently when caused by a medical condition. I have been told that with pediatric physical therapy my youngest son’s issues could be corrected allowing him more balance. We will have to wait and see once this pandemic is over to find out.